“Do you know what year they quit putting nickel in our nickels?”
Mid-1942 through 1945. Then the mint returned to the standard composition of 75% copper and 25% nickel. They are STILL making it that way, so every single nickel except the ones mentioned above are worth at least $0.09 in melt value (though it is illegal to melt them, at least now); the ones above were made with 35% silver, and are currently worth about $1.41 each...and, yes, you can still occasionally find one in circulation, though they are very rare. To do that, you need to buy boxes of nickels on a regular basis ($100 for 50 rolls) and hope that the bank gives you circulated coins instead of brand new stock from the Mint.